Co-reporter:Jianqiao Zhou, Yulu Liang, Xiwen He, Langxing Chen, and Yukui Zhang
ACS Sustainable Chemistry & Engineering December 4, 2017 Volume 5(Issue 12) pp:11413-11413
Publication Date(Web):October 17, 2017
DOI:10.1021/acssuschemeng.7b02521
The highly specific enrichment of phosphoproteins and phosphopeptides from intricate biological systems is the precondition of in-depth phosphoproteome research. Herein, a novel dual-functionalized magnetic zirconium-based metal–organic framework (MOF) denoted as DFMMOF, with the purpose of combining the affinity of immobilized metal ion affinity chromatography (IMAC) and metal oxide affinity chromatography (MOAC) has been successfully synthesized. The inherent Zr–O cluster of DFMMOF particles acted as MOAC and the immobilized titanium(IV) ions served for IMAC. The obtained DFMMOF exhibited rapid magnetic separation (within 5 s), large surface area (237.9 m2 g–1), high binding capacity (100 mg g–1), and good postenrichment recovery (84.8%). Thanks to the strong affinity, low detection sensitivity (5 fmol) and high selectivity (β-casein/BSA with a molar ratio of 1:1000) for phosphopeptide enrichment were obtained using DFMMOF as absorbent. Moreover, the effective identification of phosphopeptides from real samples (human serum and nonfat milk) further confirmed the immense potential of DFMMOF as a promising candidate for the detection and extraction of trace amounts of phosphorylated peptides in complex biosamples.Keywords: Enrichment; Immobilized metal ion affinity chromatography; Magnetic nanomaterials; Metal oxide affinity chromatography; Metal−organic framework; Phosphopeptide;
Co-reporter:Lifang Chang, Xiwen He, Langxing Chen, Yukui Zhang
Sensors and Actuators B: Chemical 2017 Volume 250(Volume 250) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.snb.2017.04.153
•A simple fluorescence FRET probe between the Mn-doped ZnS QDs and AuNPs for glycoproteins detection.•The FRET probe can determine down to 10−9 M glycoproteins.•The widely linear range of 0.0–0.5 μM and 0.0–2.4 μM for AGP and IgG, respectively.•High selectivity and anti-interference ability in AGP detection in serum.A simple fluorescent probe based on fluorescence resonance energy transfer (FRET) between the glucosamine-Mn-doped ZnS QDs and mercaptophenylboronic acid (MBA)-capped AuNPs was designed for the determination of glycoproteins such as immunoglobulin G (IgG), transferrin (Trf), α1-acid glycoprotein (AGP) and horseradish peroxidase (HRP). The FRET process took place via interaction between the glucosamine on the surface of QDs and boronic acid moieties on AuNPs surface, and resulted in the fluorescence quenched of the QDs. The FRET efficiency from QDs to AuNPs was calculated to be 75.4%. However, the FRET process would be inhibited after glycoproteins were introduced into the QDs-AuNPs system. The stronger interaction between the MBA on the surface of AuNPs and glycoproteins would keep the AuNPs far away from the QDs surface, leading to the fluorescence recovered of the QDs. The as-prepared sensor showed a high sensitivity and selectivity for glycoproteins. The dissociation constants and the detection limits of the selected standard glycoproteins (Trf, HRP, IgG and AGP) were estimated to be around 10−7 M and 10−9 M, respectively. Finally, this sensor has been successfully used for the determination of the AGP in serum samples without any complicated pretreatment and the recovery was in the range of 70%–105%.A simple fluorescence probe based on fluorescence resonance energy transfer (FRET) from the Mn-doped ZnS QDs to mercaptophenylboronic acid (MBA)-capped AuNPs was designed for the sensitive and selective determination of glycoproteins.Download high-res image (74KB)Download full-size image
Co-reporter:Jingai yang, Xiwen He, Langxing Chen, Yukui Zhang
Journal of Chromatography A 2017 Volume 1513(Volume 1513) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.chroma.2017.07.026
•The silica nanoparticle-graphene oxide composite (GO@MPBA) was obtained via thiol-yne click (TYC) reaction.•The structure and affinity properties of GO@MPBA were characterized.•GO@MPBA exhibited the high binding capacity and selectivity towards glycoproteins.•GO@MPBA showed good reusability as protein adsorbent.•Enrichment of glycoproteins from the biological samples.In this work, a facile novel strategy is developed for the preparation of 4-mercapto-phenylboronic acid functionalized silica nanoparticle-graphene oxide composite (GO@MPBA) via thiol-yne click reaction. The morphology, structure and composition of the resulting GO@MPBA was characterized by transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, Fourier transform Raman spectroscopy, Thermogravimetric analysis and X-ray photoelectron spectrometry. GO@MPBA exhibited the high binding capacity towards glycoproteins such as ovalbumin (1288.8 mg g−1), immunoglobulin G (1144.1 mg g−1), transferrin (592.1 mg g−1) and horseradish peroxidase (392.4 mg g−1), in contrast, the binding capacity of each non-glycoproteins (cytochrome c, deoxyribonuclease A, pepsin, trypsin, lysozyme and bovine serum albumin) is less than 50 mg g−1. Furthermore, the GO@MPBA still remained a good binding capacity after the five times of adsorption-desorption cycles. The selective enrichment of glycoproteins from real egg white samples by GO@MPBA was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. This work could present a facile novel approach of surface modification to design environmentally friendly and more efficient adsorbents for the isolation and enrichment of glycoprotein from complex biological samples.
Co-reporter:Lifang Chang, Haocheng Wu, Xiwen He, Langxing Chen, Yukui Zhang
Analytica Chimica Acta 2017 Volume 995(Volume 995) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.aca.2017.09.037
•The first bullet point can be changed into: A fluorescence turn-on sensor for the sensitive detection of glycoproteins.•The limit of detection of the selected glycoproteins was lower than 0.1 nM.•The sensor could be applied in a wide pH range of 5.0–9.0.•High selectivity and anti-interference ability in TRF detection in serum.A simple fluorescence turn-on sensor has been designed for the highly sensitive detection of glycoproteins on the basis of boronic acid functional polymer capped Mn-doped ZnS quantum dots (QDs@MPS@AAPBA). In the absence of glycoproteins, the fluorescence emission intensity of the QDs@MPS@AAPBA was relatively weaker due to the effective electronic transfer from the QDs to the boron moieties on its surface. While the glycoproteins were introduced into the system, an obvious fluorescence enhancement was observed. It was attributed to the boron moieties covalent binding glycans of the glycoproteins resulting in the electronic transfer process being inhibited. Under the optimal conditions, this fluorescent probe not only could be applied in a wide pH range of 5.0–9.0, but also the binding constants and detection limits of the QDs@MPS@AAPBA for horseradish peroxidase (HRP) and transferrin (TRF) were up to 7.23 × 106 M−1, 1.53 × 107 M−1 and 1.44 × 10−10 M, 3.36 × 10−10 M, respectively. Finally, this proposed method has also been utilized for the TRF determination in serum without any complicated pretreatment and the recovery was in the range of 95.7%–103.0%. As a result, it is promising for application on the glycoproteins detection in complex biological samples.Download high-res image (185KB)Download full-size image
Co-reporter:Lifang Chang;Xiwen He;Langxing Chen;Yukui Zhang
Nanoscale (2009-Present) 2017 vol. 9(Issue 11) pp:3881-3888
Publication Date(Web):2017/03/17
DOI:10.1039/C6NR09944K
A novel fluorescent turn-on biosensor based on fluorescence resonance energy transfer (FRET) from GSH functionalized Mn-doped ZnS QDs to graphene oxide (GO) was constructed to determine glutathione S-transferases (GSTs) in live cells and human urine. The QDs@GSH is adsorbed on the GO surface via hydrogen bonding interaction between the GSH on the surface of QDs@GSH and GO, and as a result, fluorescence quenching of the QDs@GSH takes place because of FRET. The FRET efficiency from QDs@GSH to GO was calculated to be 86.3%. However, in the presence of GSTs, the FRET process could be inhibited by the specific interaction between the GSH on the surface of QDs@GSH and GSTs, which would keep the QDs@GSH far away from the GO surface, leading to the recovery of the fluorescence. The proposed sensor exhibited high sensitivity, selectivity, and excellent specificity in the buffer, live cells and human urine for the detection of GSTs. Under the physiological conditions (pH 7.4), dissociation constants and the detection limit of GST and ATP6 V1F (a GST-tagged protein) were estimated to be 8.0 × 10−9 M, 2.1 × 10−10 M and 3.5 × 10−9 M, 7.2 × 10−11 M, respectively. The presented method has been successfully utilized for the determination of the GSTs in live cells and human urine without any complicated pretreatment and the recovery was in the range of 80%–90%.
Co-reporter:Yanchao Mayang;Xiwen He;Langxing Chen;Yukui Zhang
Microchimica Acta 2017 Volume 184( Issue 8) pp:2749-2757
Publication Date(Web):03 May 2017
DOI:10.1007/s00604-017-2275-3
A surface plasmon resonance sensor whose surface has been modified with boronic acid groups was developed in order to bind and detect transferrin. 4-Mercaptophenylboronic acid (4-MPBA) was utilized to form a self-assembled monolayer on the gold surface of the sensor chip. The surface topography of the modified gold chip was characterized by atomic force microscopy. In solutions of pH 9, the glycosyl groups of transferrin (Trf) quickly and reversibly combine with 4-MPBA on the sensor chip to result in changes of the refractive index. Thus, Trf can be sensed online by monitoring the SPR signal. Under optimized conditions, the sensor has a linear response in the 10 nM to 1.3 μM Trf concentration range, and the limit of detection is 4.4 nM (equivalent to 0.34 μg·mL−1). The results suggest that this 4-MPBA-functionalized sensor is a viable candidate for clinical testing of Trf which is a potential marker for severe diseases such as hypertension, primary renal disease, and diabetes.
Co-reporter:Lifang Chang, Xiwen He, Langxing Chen, Yukui Zhang
Sensors and Actuators B: Chemical 2017 Volume 243() pp:72-77
Publication Date(Web):May 2017
DOI:10.1016/j.snb.2016.11.121
•A novel turn-on fluorescent enhanced sensor for the detection of glycoprotein TRF.•The MBA@QDs can sensitively detect down to 5.69 × 10−9 M TRF.•The linear range for TRF is 0.10–10.0 μM.•High selectivity and anti-interference ability.•The application of TRF detection in serum.In this work, a novel fluorescent turn-on sensor for the detection of glycoproteins based upon measuring the fluorescence enhancement of mercaptophenylboronic acid-capped Mn-doped ZnS quantum dots (QDs@MBA) was developed. Transferrin (TRF), as one of glycoproteins, was introduced to evaluate characteristics of the fluorescent probe. The TRF bound onto MBA via boronate affinity interaction can efficiently enhance the fluorescence of QDs@MBA through a blocked electron transfer process from the QDs to the boronic acid moieties. Approximately 2.6-fold fluorescence enhancement of QDs@MBA at 610 nm can be observed in presence of 10.0 μM TRF within 10 min. The QDs@MBA can sensitively detect down to 5.69 × 10−9 M TRF in aqueous solution and the linear range is 0.10–10.0 μM. Moreover, QDs@MBA was also applied to detect TRF in serum sample, and the recovery can achieve 87.9%–96.5%. This sensor shows a great potential for detecting glyproteins present in the complex biological or biomedical samples.A novel fluorescent sensor to detect glycoproteins based upon measuring the fluorescence enhancement of mercaptophenylboronic acid-capped Mn-doped ZnS quantum dots (QDs@MBA) was developed. The TRF bound onto MBA via boronate affinity interaction can efficiently enhance the fluorescence of QDs@MBA through a blocked electron transfer process from the QDs to the boronic acid moieties.
Co-reporter:Long Qin, Xiwen He, Langxing Chen, and Yukui Zhang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 10) pp:5965
Publication Date(Web):March 2, 2015
DOI:10.1021/acsami.5b00269
A fluorescence resonance energy transfer (FRET) method based on gold nanoclusters capped glutathione (AuNCs@GSH) and amine-terminated gold nanorods (AuNRs) is designed for turn-on and near-infrared region (NIR) sensing of glutathione S-transferase (GST). The absorption band of AuNRs is tuned carefully to maximize the spectra overlap and enhance the efficiency of FRET. The FRET from multiple AuNCs to single AuNR quenches about 70% fluorescence emission of AuNCs. After GST is added, the strong specific interaction of GSH–GST can replace the AuNCs@GSH from AuNRs, FRET based on electrostatic interaction between AuNCs@GSH and AuNRs is switched off. Thus, emission enhancement of AuNCs@GSH is observed. The fluorescent enhancement is linearly with the increasing GST concentration over the range of 2–100 nM GST and the limit of detection for GST is about 1.5 nM.Keywords: fluorescence resonance energy transfer; glutathione S-transferase; gold nanoclusters; gold nanorods; near-infrared
Co-reporter:Changfen Bi, Yingran Zhao, Lijin Shen, Kai Zhang, Xiwen He, Langxing Chen, and Yukui Zhang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 44) pp:24670
Publication Date(Web):October 19, 2015
DOI:10.1021/acsami.5b06991
The development of methods to isolate and enrich low-abundance glycopeptides from biological samples is crucial to glycoproteomics. Herein, we present an easy and one-step surface modification strategy to prepare hydrophilic maltose functionalized Fe3O4 nanoparticles (NPs). First, based on the chelation of the catechol ligand with iron atoms, azido-terminated dopamine (DA) derivative was assembled on the surface of magnetic Fe3O4 nanoparticles by sonication. Second, the hydrophilic maltose-functionalized Fe3O4 (Fe3O4-DA-Maltose) NPs were obtained via copper(I)-catalyzed azide–alkyne cycloaddition (click chemistry). The morphology, structure, and composition of Fe3O4-DA-Maltose NPs were investigated by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectrometer (XPS), and vibrating sample magnetometer (VSM). Meanwhile, hydrophilicity of the obtained NPs was evaluated by water contact angle measurement. The hydrophilic Fe3O4-DA-Maltose NPs were applied in isolation and enrichment of glycopeptides from horseradish peroxidase (HRP), immunoglobulin (IgG) digests. The MALDI-TOF mass spectrometric analysis indicated that the novel NPs exhibited high detection sensitivity in enrichment from HRP digests at concentration as low as 0.05 ng μL–1, a large binding capacity up to 43 mg g–1, and good recovery for glycopeptides enrichment (85–110%). Moreover, the Fe3O4-DA-Maltose NPs were applied to enrich glycopeptides from human renal mesangial cells (HRMC) for identification of N-glycosylation sites. Finally, we identified 115 different N-linked glycopeptides, representing 93 gene products and 124 glycosylation sites in HRMC.Keywords: copper(I)-catalyzed azide−alkyne cycloaddition (CuAAC); dopamine; enrichment; Fe3O4 nanoparticles; glycopeptides; maltose
Co-reporter:Xihao Zhang, Jiewen Wang, Xiwen He, Langxing Chen, and Yukui Zhang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 44) pp:24576
Publication Date(Web):October 19, 2015
DOI:10.1021/acsami.5b06445
Biomedical sciences, and in particular biomarker research, demand efficient glycoproteins enrichment platforms. In this work, we present a facile and time-saving method to synthesize phenylboronic acid and copolymer multifunctionalized magnetic nanoparticles (NPs) using a distillation–precipitation polymerization (DPP) technique. The polymer shell is obtained through copolymerization of two monomers-affinity ligand 3-acrylaminophenylboronic acid (AAPBA) and a hydrophilic functional monomer. The resulting hydrophilic Fe3O4@P(AAPBA-co-monomer) NPs exhibit an enhanced binding capacity toward glycoproteins by an additional functional monomer complementary to the surface presentation of the target protein. The effects of monomer ratio of AAPBA to hydrophilic comonomers on the binding of glycoproteins are systematically investigated. The morphology, structure, and composition of all the synthesized microspheres are characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The hydrophilic Fe3O4@P(AAPBA-co-monomer) microspheres show an excellent performance in the separation of glycoproteins with high binding capacity; And strong magnetic response allows them to be easily separated from solution in the presence of an external magnetic field. Moreover, both synthetic Fe3O4@P(AAPBA) and copolymeric NPs show good adsorption to glycoproteins in physiological conditions (pH 7.4). The Fe3O4@P(AAPBA-co-monomer) NPs are successfully utilized to selectively capture and identify the low-abundance glycopeptides from the tryptic digest of horseradish peroxidase (HRP). In addition, the selective isolation and enrichment of glycoproteins from the egg white samples at physiological condition is obtained by Fe3O4@P(AAPBA-co-monomer) NPs as adsorbents.Keywords: Boronate; Distillation−precipitation polymerization; Enrichment; Glycopeptides; Glycoproteins; Magnetic particles
Co-reporter:Yingran Zhao, Changfen Bi, Xiwen He, Langxing Chen and Yukui Zhang
RSC Advances 2015 vol. 5(Issue 86) pp:70309-70318
Publication Date(Web):12 Aug 2015
DOI:10.1039/C5RA13183A
In this work, we present a general method to prepare core–shell molecularly imprinted polymers (MIPs) on the surface of magnetic carbon nanotubes (MCNTs@MIP) for sulfamethoxazole (SMO). The resulting MCNTs@MIP possess a highly improved imprinting effect, fast adsorption kinetics and high adsorption capacity, and can be applied to rapidly extract sulfonamide in milk and honey samples under an external magnetic field. The morphology, adsorption capacity and recognition properties of MCNTs@MIP composites were investigated by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectrometry, X-ray diffraction (XRD), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), and re-binding experiments. The resulting MCNTs@MIP showed a good accessibility for the binding sites, a maximum adsorption capacity of MCNTs@MIP for SMO was 864.9 μg g−1, and a high selectivity toward the template molecule (SMO) in the presence of the structurally related sulfonamides (imprinting factor = 10.0). A method was developed for enrichment and determination of SMO in the milk and honey samples with recoveries ranging from 68.3 to 78.2% and 73.9 to 80.1%, respectively and relative standard deviations (RSD) < 6.8%.
Co-reporter:Xuedong Mao, Hongyu Sun, Xiwen He, Langxing Chen and Yukui Zhang
Analytical Methods 2015 vol. 7(Issue 11) pp:4708-4716
Publication Date(Web):30 Apr 2015
DOI:10.1039/C5AY00590F
In this work, a novel kind of core–shell magnetic molecularly imprinted polymer (MIP) for sulfamethazine (SMZ) was synthesized by the surface-initiated atom transfer radical polymerization (ATRP) strategy. In this protocol, polydopamine was formed on the Fe3O4 nanoparticles (NPs) in 10 mM Tris–HCl buffer solution (pH 8.5). The initiator bromide reagent of ATRP was then grafted onto the polydopamine surface. Finally, the MIP layer was formed on the surface of Fe3O4 by the copolymerization of sulfamethazine as a template, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a cross-linking agent using an organometallic catalyst comprising Cu(I)Br and pentamethyldiethylenetriamine. The morphology and magnetic, adsorption and recognition properties of Fe3O4@SMZ-MIP NPs were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, vibrating sample magnetometry (VSM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and re-binding experiments. The controllable nature of ATRP allows the growth of a uniform MIP layer with adjustable thickness, providing a large adsorption capacity (680.27 μg g−1), fast kinetics about 40 min to equilibrium, and a considerably high imprinting factor of 17.02. The feasibility of the enrichment of sulfonamides by Fe3O4@SMZ-MIP was demonstrated using egg samples spiked with SMZ and SMR. The recoveries of SMZ and SMR ranged from 76.7 to 93.0% and 69.3 to 77.2%, respectively, and the relative standard deviations (RSD) were <7.0%. In addition, Fe3O4@SMZ-MIP showed good reusability for at least five repeated cycles.
Co-reporter:Xihao Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2014 vol. 2(Issue 21) pp:3254-3262
Publication Date(Web):17 Mar 2014
DOI:10.1039/C4TB00379A
Biomedical sciences, and in particular biomarker research, demand efficient glycoprotein enrichment platforms. In this paper, a facile and efficient approach combining distillation–precipitation polymerization (DPP) and click chemistry was developed to synthesize boronic acid ligand-modified magnetic nanoparticles for the enrichment of glycoproteins. Due to the relatively large amount of benzyl chloride groups introduced by DPP on the magnetic core, which easily can be transferred into azide groups, the alkyne–phenylboronic acid ligands were immobilized onto the surface of Fe3O4 with high efficiency via the Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) ‘click’ reaction. The morphology, structure and composition of the resulting core–shell Fe3O4@poly(4-vinylbenylchloride)@amidophenylboronic acid (Fe3O4@pVBC@APBA) nanocomposites were characterized by transmission electron microscopy, X-ray powder diffraction, vibrating sample magnetometry, Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray photoelectron spectrometry. The Fe3O4@pVBC@APBA microspheres held a ∼50 nm polymeric shell, and exhibited high magnetic response to an external magnetic field. The binding results demonstrated that Fe3O4@pVBC@APBA possessed high adsorption capacity and remarkable selectivity to glycoproteins. Moreover, the glycoproteins in the egg white sample could be enriched under physiological conditions (pH 7.4) as well, due to the lower pKa value of the alkyne–phenylboronic acid ligand. The high stability and selectivity of Fe3O4@pVBC@APBA for the glycoproteins were retained over several separation cycles. This boronate affinity material has potential applications in biomedical and biotechnological fields including drug delivery and biosensing.
Co-reporter:Yulu Liang, Xiwen He, Langxing Chen and Yukui Zhang
RSC Advances 2014 vol. 4(Issue 100) pp:56883-56891
Publication Date(Web):14 Oct 2014
DOI:10.1039/C4RA08258C
Microcystins (MCs), a family of potent cyclic heptapeptides, are produced by cyanobacteria blooms in eutrophic water and can cause acute and chronic toxicity and even mortality to animals and humans. Previous MC removal strategies concerned only highly contaminated water, in which the concentration of the pollutant was considerably larger than that in the natural world. Herein, we developed a ternary composite of TiO2-coated magnetic graphene and used it as an adsorbent and photocatalyst to efficiently remove microcystin-LR (MC-LR) from water. The two-dimensional sheets of graphene were decorated with a large quantity of spherical Fe3O4 nanoparticles (10–20 nm) and then coated with crystallized TiO2. These TiO2–graphene@Fe3O4 composites exhibited a high magnetic response to the external magnetic field. And the huge surface of the graphene dramatically boosted the adsorbability and charge mobility, which lowered the recombination rate of electron–hole pairs, and hence systematically enhanced photocatalytic activity. The combination of adsorption and photodegradation endowed the composite with a better performance in the removal of trace amounts of MC-LR than the commercial photocatalyst, Degussa P25. The concentration of MC-LR can be lowered to less than 1 μg L−1 (a provisional safety guideline by the World Health Organization) from 500 μg L−1 under UV light in 30 min. The loading of TiO2–graphene@Fe3O4, the pH, and the UV energy were also optimized. Moreover, the stable removal capability of TiO2–graphene@Fe3O4 was confirmed over multiple cycles. Finally, the removal performance was also evaluated under natural light illumination in real surface water samples. This work paves the way for the development of more efficient and easily separable purifiers for the removal of pollutants and toxins from contaminated water.
Co-reporter:Yulu Liang, Xiwen He, Langxing Chen and Yukui Zhang
RSC Advances 2014 vol. 4(Issue 35) pp:18132-18135
Publication Date(Web):09 Apr 2014
DOI:10.1039/C4RA01573H
A novel multifunctional graphene/Fe3O4/TiO2 composite with excellent hydrophilicity and biological compatibility was synthesized and applied to the fast, highly selective and sensitive enrichment of phosphopeptides from biosamples.
Co-reporter:Sitong Zhang, Xiwen He, Langxing Chen and Yukui Zhang
New Journal of Chemistry 2014 vol. 38(Issue 9) pp:4212-4218
Publication Date(Web):16 May 2014
DOI:10.1039/C4NJ00424H
A simple, novel approach was developed for the preparation of boronic acid functionalized Fe3O4 magnetic nanoparticles (MNPs) via thiol–ene (TE) click reaction. In this work, two clickable Fe3O4 MNPs functionalized with either alkene or thiol moieties were synthesized. Firstly, Fe3O4 MNPs were synthesized through a solvothermal method and then the clickable alkene- or thiol-coated Fe3O4 MNPs were prepared by sol–gel reaction with an organosilicon coupling agent, 3-(methacryloyloxy) propyltrimethoxylsilane (MPS) or 3-mercaptopropyltriethoxysilane (MPTES). The carbon–carbon double bonds/thiol groups on the surface of the MNPs serve as clickable sites to react with 4-mercaptophenylboronic acid (4-MPBA)/3-acrylamidophenylboronic acid (AAPBA) during the subsequent TE click reaction. Finally, the high density of boronic acid ligands immobilized on the surface of the Fe3O4 MNPs was obtained via TE click reactions. The morphology, adsorption and recognition properties of the Fe3O4 MNPs were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM) and X-ray photoelectron spectrometry (XPS). Four proteins, including ovalbumin (OB) and transferrin (Trf) as glycoprotein templates, and lysozyme (Lyz) and horse heart cytochrome c (Cyt C) as non-glycoprotein templates are chosen as target proteins. Two types of click-Fe3O4 MNP (Fe3O4@MPS@PBA and Fe3O4@SH@AAPBA) exhibit a high binding capacity and excellent specificity towards glycoproteins, and can selectively capture and separate glycoproteins from egg white samples directly. Furthermore, this work could provide a promising method of surface modification for the design of more efficient adsorbents for the isolation and enrichment of proteins from complex bio-samples.
Co-reporter:Jiali Cao;Xihao Zhang; Xiwen He; Langxing Chen; Yukui Zhang
Chemistry – An Asian Journal 2014 Volume 9( Issue 2) pp:526-533
Publication Date(Web):
DOI:10.1002/asia.201300937
Abstract
A protein imprinting approach for the synthesis of core–shell structure nanoparticles with a magnetic core and molecularly imprinted polymer (MIP) shell was developed using a simple distillation–precipitation polymerization method. In this work, Fe3O4 magnetic nanoparticles were first synthesized through a solvothermal method and then were conveniently surface-modified with 3-(methacryloyloxy)propyltrimethoxylsilane as anchor molecules to donate vinyl groups. Next a high-density MIP shell was coated onto the surface of the magnetic nanoparticles by the copolymerization of functional monomer acrylamide (AAm), cross-linking agent N,N′-methylenebisacrylamide (MBA), the initiator azodiisobutyronitrile (AIBN), and protein in acetonitrile heated at reflux. The morphology, adsorption, and recognition properties of the magnetic molecularly imprinted nanoparticles were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and rebinding experiments. The resulting MIP showed a high adsorption capacity (104.8 mg g−1) and specific recognition (imprinting factor=7.6) to lysozyme (Lyz). The as-prepared Fe3O4@Lyz-MIP nanoparticles with a mean diameter of 320 nm were coated with an MIP shell that was 20 nm thick, which enabled Fe3O4@Lyz-MIP to easily reach adsorption equilibrium. The high magnetization saturation (40.35 emu g−1) endows the materials with the convenience of magnetic separation under an external magnetic field and allows them to be subsequently reused. Furthermore, Fe3O4@Lyz-MIP could selectively extract a target protein from real egg-white samples under an external magnetic field.
Co-reporter:Jiali Cao, Xihao Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2013 vol. 1(Issue 30) pp:3625-3632
Publication Date(Web):03 Jun 2013
DOI:10.1039/C3TB20573H
In this study, a facile and efficient separation of abundant proteins from bovine blood using core–shell structure nanoparticles with a magnetic core and an immobilized metal affinity ligand iminodiacetic acid (IDA) chelating Ni(II) is presented. Firstly, Fe3O4 magnetic nanoparticles (MNPs) were synthesized through a solvothermal method and then were conveniently surface-modified with 3-(methacryloyloxy) propyltrimethoxylsilane as anchor molecules to donate vinyl groups. Next a high density poly(4-vinylbenzylchloride) (PVBC) shell was synthesized on the surface of silica-coated Fe3O4 MNPs via distillation–precipitation polymerization. After the PVBC shell reacted with iminodiacetic acid (IDA) in alkaline aqueous solution, the magnetite was charged with Ni2+ to form Ni(II)-IDA functionalized hybrid Fe3O4@PVBC@IDA-Ni MNPs. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and a vibrating sample magnetometer (VSM) were employed to evaluate the size, morphology and magnetic property of the resulting magnetic nanospheres. The high saturation magnetization (48.1 emu g−1) provides the materials with the convenience of magnetic separation under an external magnetic field and they can be subsequently reused. The core–shell Fe3O4@PVBC@IDA-Ni MNPs exhibit excellent performance in the separation of protein bovine hemoglobin (BHb), and the binding capacity is as high as 1988 mg g−1. In addition, the Fe3O4@PVBC@IDA-Ni MNPs can be used in selective removal of abundant protein Hb in the bovine blood samples. This opens a novel route for its future application in removing abundant protein in proteomic analysis.
Co-reporter:Yu-Xing LIU, Gui-Qin JIAN, Xi-Wen HE, Lang-Xing CHEN, Yu-Kui ZHANG
Chinese Journal of Analytical Chemistry 2013 Volume 41(Issue 2) pp:161-166
Publication Date(Web):February 2013
DOI:10.1016/S1872-2040(13)60626-X
A novel composite material based on core-shell molecularly imprinted polymers (MIPs) was prepared by combining surface imprinting technique with a sol-gel process based on carbon nanotubes (CNTs) coated with silica. The morphology and structure of the products (CNTs@Naf-MIPs) were characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The adsorption properties of CNTs@Naf-MIPs were demonstrated by equilibrium rebinding experiments and Langmuir analysis. The maximum adsorption capacity and dissociation constant of CNTs@Naf-MIPs were 9.5 mg g−1 and 56.6 mL mg−1, respectively. The CNTs@Naf-MIPs showed a fast kinetics and reached the equilibrium within only 30 min. The feasibility of determination of nafcillin from real samples was testified in spiked egg samples with concentration of 5 and 10 μg kg−1 by using the imprinted polymer as the adsorption material. The recoveries of nafcillin ranged from 61.3% to 84.3% with good accuracy. The MIPs provided a fast and convenient determination platform for nafcillin in egg samples.A novel composite material based on core-shell molecularly imprinted polymers for nafcillin (CNTs@Naf-MIPs) was prepared by combining surface imprinting with a sol-gel process based on carbon nanotubes coated with silica. The CNTs@Naf-MIPs provided a fast and convenient determination platform for nafcillin in egg samples.
Co-reporter:F. Yang;J. Mao;X. W. He;L. X. Chen
Analytical and Bioanalytical Chemistry 2013 Volume 405( Issue 21) pp:6639-6648
Publication Date(Web):2013 August
DOI:10.1007/s00216-013-7026-7
In this study, a boronate-silica hybrid affinity monolith was prepared for specific capture of glycoproteins at neutral pH condition. The monolith was synthesized via a facile one-pot procedure in a stainless steel column by concurrently mixing hydrolyzed alkoxysilanes tetramethoxysilane and vinyltrimethoxysilane, organic monomer 3-acrylamidophenylboronic acid and initiator 2,2′-azobisisobutyronitrile together. The polycondensation of alkoxysilanes and copolymerization of organic monomer and vinyl-silica monolith were carried out successively by reacting at different temperatures. After optimizing the preparation conditions, the resulting hybrid affinity monolith was systematically characterized and exhibited excellent affinity to both cis-diol-containing small molecules and glycoproteins at neutral and physiological pH, including adenosine, horseradish peroxidase, transferrin and ovalbumin. The binding capacity of ovalbumin on monolith was measured to be 2.5 mg g−1 at pH 7.0. Furthermore, the hybrid affinity monolith was applied to the separation of transferrin from bovine serum sample at a physiological condition. Good repeatability was obtained and the relative standard deviations of retention time were 1.15 and 4.77 % (n = 5) for run-to-run and column-to-column, respectively.
Co-reporter:Guiqin Jian, Yuxing Liu, Xiwen He, Langxing Chen and Yukui Zhang
Nanoscale 2012 vol. 4(Issue 20) pp:6336-6342
Publication Date(Web):15 Aug 2012
DOI:10.1039/C2NR31430D
In this study, we report a novel method to synthesize core–shell structured Fe3O4 nanoparticles (NPs) covalently functionalized with iminodiacetic acid (IDA) via click chemistry between the azide and alkyne groups and charged with Cu2+. Firstly, the Fe3O4@SiO2 NPs were obtained using tetraethoxysilane (TEOS) to form a silica shell on the surface of the Fe3O4 core. The azide group-modified Fe3O4@SiO2 NPs were obtained by a sol–gel process using 3-azidopropyltriethoxysilane (AzPTES) as the silane agent. Fe3O4@SiO2–N3 was directly reacted with N-propargyl iminodiacetic via click chemistry, in the presence of a Cu(I) catalyst, to acquire the IDA-modified Fe3O4 NPs. Finally, through the addition of Cu2+, the Fe3O4@SiO2–IDA-Cu NP product was obtained. The morphology, structure and composition of the NPs were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The resulting NPs showed a strong magnetic response to an externally applied magnetic field, a high adsorption capacity and excellent specificity towards hemoglobin (Hb). In addition, the Fe3O4@SiO2–IDA-Cu NPs can be used for the selective removal of abundant Hb protein in bovine and human blood samples.
Co-reporter:Min Zhang, Xihao Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Nanoscale 2012 vol. 4(Issue 10) pp:3141-3147
Publication Date(Web):02 Apr 2012
DOI:10.1039/C2NR30316G
In this study, we report a facile method for the preparation of core–shell magnetic molecularly imprinted polymers (MIPs) for protein recognition. Uniform carboxyl group functionalized Fe3O4 nanoparticles (NPs) were synthesized using a solvothermal method. Magnetic MIPs were synthesized by self-polymerization of dopamine in the presence of template protein on the surface of the Fe3O4 NPs. A thin layer of polydopamine can be coated on Fe3O4 NPs via dopamine self-polymerization and the imprinted polydopamine shells can be controlled by the mass ratio of Fe3O4 NPs and dopamine. More importantly, there is a critical value of polydopamine shell thickness for the maximum rebinding capacity. The as-prepared lysozyme-imprinted Fe3O4@polydopamine NPs show high binding capacity and acceptable specific recognition behavior towards template proteins. This method provides the possibility for the separation and enrichment of abundant proteins in proteomic analysis.
Co-reporter:Xihao Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2012 vol. 22(Issue 32) pp:16520-16526
Publication Date(Web):13 Jul 2012
DOI:10.1039/C2JM32987E
In this study, a novel approach was developed to synthesize aminophenylboronic acid functionalized magnetic nanoparticles (NPs) via Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) ‘click’ chemistry. Firstly, azide-functional Fe3O4 NPs were obtained by a two-step chemical modification process. Then, an alkyne-phenylboronic acid molecule was connected onto the surface of magnetite by the CuAAC reaction. The morphology, structure and composition of the synthesized nanocomposites were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectrometry (XPS). Five proteins, including ovalbumin (OB), transferrin (Trf), as glycoprotein templates and lysozyme (Lyz), bovine serum albumin (BSA), horse heart cytochrome c (Cyt C) as nonglycoprotein templates are chosen as target proteins. The as-prepared click-Fe3O4@APBA NPs with a mean diameter of 23.2 nm showed a strong magnetic response to an externally applied magnetic field and exhibited a high adsorption capacity and excellent specificity towards glycoproteins in comparison with nonglycoproteins. The click-Fe3O4@APBA NPs showed the higher adsorption capacity towards glycoproteins than the nonclick-Fe3O4@APBA NPs which were synthesized through a common nucleophilic substitution reaction. The greatly enhanced adsorption capacity towards glycoproteins demonstrated that the ‘click’ method presented great superiority in ligand immobilization. Finally, the click-Fe3O4@APBA NPs could efficiently enrich glycoproteins from real egg white samples as well.
Co-reporter:Xuan Kong, Ruixia Gao, Xiwen He, Langxing Chen, Yukui Zhang
Journal of Chromatography A 2012 Volume 1245() pp:8-16
Publication Date(Web):6 July 2012
DOI:10.1016/j.chroma.2012.04.061
In this study, we present a general method to prepare the core–shell magnetic molecularly imprinted polymers (MIPs) nanoparticles (NPs) for sulfamethazine (SMZ). The resulting Fe3O4@MIPs NPs possess a highly improved imprinting effect, fast adsorption kinetics and high adsorption capacity, and can be applied to extract sulfonamide in the poultry feed. In this protocol, the magnetite NPs were synthesized by co-precipitating Fe2+ and Fe3+ in an ammonia solution first. Silica was then coated on the Fe3O4 NPs using a sol–gel method to obtain silica shell magnetic NPs. Subsequently, the vinyl groups were grated onto silica-modified Fe3O4 surface by 3-methacryloyloxypropyltrimethoxysilane. Finally, the MIPs films were formed on the surface of Fe3O4@SiO2 by the copolymerization of vinyl end groups with functional monomer, methacrylic acid, cross-linking agent, ethylene glycol dimethacrylate, the initiator azo-bis-isobutyronitrile and template molecule, sulfamethazine. The morphology, magnetic, adsorption and recognition properties of Fe3O4@MIPs NPs were characterized using transmission electron microscope (TEM), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectrometer, vibrating sample magnetometer (VSM) and re-binding experiments. The results showed that the binding sites of Fe3O4@MIPs were good accessibility, fast adsorption rate and the maximum adsorption capacity of Fe3O4@MIPs to SMZ was 344.8 μg g−1. The selectivity of the obtained Fe3O4@MIPs NPs were elucidated by the different rebinding capability of SMZ and structural related sulfonamides in the mixed solution. The results indicated that the Fe3O4@MIPs had high imprinting factor 9.5 and significant selectivity. A method was developed for enrichment and determination of SMZ in the poultry feed samples with recoveries of duck and chicken feed ranging from 63.3 to 76.5% and 68.7 to 74.7%, respectively and the relative standard deviations (RSD) (<6.7%).Highlights► We present a general method to prepare the core–shell magnetic MIPs nanoparticles (Fe3O4@MIPs) for sulfamethazine. ► The Fe3O4@MIPs possess a highly improved imprinting factor, fast adsorption kinetics and high adsorption capacity. ► The structure and affinity properties of the resulting Fe3O4@MIPs were characterized. ► We used Fe3O4@MIPs for enrichment and determination of SMZ in the poultry feed samples.
Co-reporter:Ruixia Gao, Xuan Kong, Xin Wang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2011 vol. 21(Issue 44) pp:17863-17871
Publication Date(Web):05 Oct 2011
DOI:10.1039/C1JM12414E
A general method to prepare thin, molecularly imprinted polymer (MIP) coatings on magnetic Fe3O4 nanoparticles (NPs) with a uniform core–shell structure for the recognition and enrichment of protein was developed. Four proteins (bovine serum albumin (BSA, pI = 4.9), bovine hemoglobin (BHb, pI = 6.9), bovine pancreas ribonuclease A (RNase A, pI = 9.4) and lysozyme (Lyz, pI = 11.2)) with different isoelectric points were chosen as the templates. The magnetic protein-MIPs were synthesized by combining surface imprinting and sol–gel techniques. The morphology, adsorption and recognition properties of the magnetic molecularly imprinted NPs were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy and through the use of a vibrating sample magnetometer (VSM). In comparison with the use of Lyz, BSA and RNase A as template proteins, BHb-imprinted Fe3O4 showed the best imprinting effect and the highest adsorption capacity among the four proteins. The as-prepared Fe3O4@BHb-MIPs NPs with a mean diameter of 230 nm were coated with an MIP shell that was 10 nm thick, which enabled the Fe3O4@BHb-MIPs to easily reach adsorption equilibrium. A high magnetic saturation value of 25.47 emu g−1 for Fe3O4@BHb-MIPs NPs was obtained, which endowed the adsorbent with the convenience of magnetic separation under an external magnetic field. The resultant Fe3O4@BHb-MIPs NPs could not only selectively extract a target protein from mixed proteins but also specifically capture the protein BHb from a real sample of bovine blood. In addition, different batches of magnetic MIPs showed good reproducibility and reusability for at least six repeated cycles.
Co-reporter:Fan Yang, Zian Lin, Xiwen He, Langxing Chen, Yukui Zhang
Journal of Chromatography A 2011 Volume 1218(Issue 51) pp:9194-9201
Publication Date(Web):23 December 2011
DOI:10.1016/j.chroma.2011.10.049
A macroporous boronate affinity monolithic column was prepared and applied to specifically capture glycoproteins using metal-organic gels (MOGs) as a porogenic template. This newly explored application of MOGs has proven to be a more convenient method for the formation of macropores in contrast to traditional porogenic methods. The poly (3-acrylamidophenylboronic acid-co-ethylene dimethacrylate) monolithic columns were synthesized in stainless columns by in situ polymerization. To fabricate the macroporous formation with a uniformed open-channel network, the preparation conditions, such as reaction temperature, the concentration of the MOGs and the ratio of monomers were systematically investigated. The prepared macroporous monoliths were characterized by scanning electron microscope (SEM) and mercury intrusion porosimetry. Furthermore, horseradish peroxidase (HRP) and transferrin (TF) were chosen as test glycoproteins, and the chromatographic analysis demonstrated that the macroporous boronate affinity monoliths exhibited a higher selectivity and better dynamic binding capacity toward glycoproteins compared with non-glycoproteins. The resulted affinity monolithic column was successfully employed to specifically capture TF from a bovine serum sample.Highlights► An alternative method was developed for the synthesis of a macroporous boronate affinity monolithic column in a convenient way using MOG as a porogenic template. ► The monolithic column had the advantage of good macropore distribution and permeability for further high-throughput and efficient separations of glycoproteins. ► A one-step purification of transferrin from bovine serum sample was of success.
Co-reporter:Xiangli Sun;Xiwen He;Langxing Chen;Yukui Zhang
Analytical and Bioanalytical Chemistry 2011 Volume 399( Issue 10) pp:3407-3413
Publication Date(Web):2011 April
DOI:10.1007/s00216-010-4390-4
Two types of macroporous organic polymer monoliths based on glycidyl methacrylate (GMA), 4-vinylbenzyl chloride (VBC) and divinylbenzene (DVB) were prepared inside stainless-steel tubes. Azide functionalities were firstly introduced on the surfaces of poly(GMA-co-DVB) and poly(VBC-co-DVB) monoliths to provide reactive sites for click chemistry. With the application of copper(I)-catalyzed (3 + 2) azide-alkyne cycloaddition, an in-column click-modification approach for covalent attachment of long alkyl chains onto polymer monoliths was developed. The column morphology and surface chemistry of the fabricated monolithic columns were characterized by the scanning electron microscopy, mercury intrusion porosimeter, Fourier transform infrared spectroscopy, and elemental analyses, respectively. The chromatographic performances of the “clicked” stationary phases were demonstrated with the high separation efficiency for a variety of proteins within 4 min.
Co-reporter:Ruixia Gao, Xiaoqian Su, Xiwen He, Langxing Chen, Yukui Zhang
Talanta 2011 Volume 83(Issue 3) pp:757-764
Publication Date(Web):15 January 2011
DOI:10.1016/j.talanta.2010.10.034
This paper reports the preparation of carbon nanotubes (CNTs) functionalized with molecularly imprinted polymers (MIPs) for advanced removal of estrone. CNTs@Est-MIPs nanocomposites with a well-defined core–shell structure were obtained using a semi-covalent imprinting strategy, which employed a thermally reversible covalent bond at the surface of silica-coated CNTs for a large-scale production. The morphology and structure of the products were characterised by transmission electron microscopy and Fourier transform infrared spectroscopy. The adsorption properties were demonstrated by equilibrium rebinding experiments and Scatchard analysis. The results demonstrate that the imprinted nanocomposites possess favourable selectivity, high capacity and fast kinetics for template molecule uptake, yielding an adsorption capacity of 113.5 μmol/g. The synthetic process is quite simple, and the different batches of synthesized CNTs@Est-MIPs nanocomposites showed good reproducibility in template binding. The feasibility of removing estrogenic compounds from environmental water using the CNTs@Est-MIPs nanocomposites was demonstrated using water samples spiked with estrone.
Co-reporter:Min Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2010 vol. 20(Issue 47) pp:10696-10704
Publication Date(Web):04 Oct 2010
DOI:10.1039/C0JM01336F
In this study, we report a method to synthesize core–satellite structured Fe3O4/polydopamine/Au composite nanoparticles (NPs). Firstly, the Fe3O4/polydopamine composite NPs with a well-defined core–shell structure are obtained using dopamine self-polymerization to form thin, surface-adherent polydopamine films onto the surface of a Fe3O4 “core”. The polydopamine shell could be adjusted by controlling the experimental parameters such as reaction time and the reactant concentrations. Then, numerous “satellites” of gold nanoparticles were assembled on the surface of Fe3O4/polydopamine by reducing Au3+ between the Fe3O4/polydopamine solid and HAuCl4 solution. Next, 11-mercaptoundecanoic acid (11-MUA) forms a self-assembled monolayer of MUA on the surface of the Au NPs and polydopamine layer. Finally, IDA-Cu functionalized Fe3O4/polydopamine/Au composite NPs are obtained by the carboxyl groups of MUA reacting with iminodiacetic acid (IDA), charged with Cu2+. The IDA-Cu groups, acting as an “anchor”, are attached on the gold and the polydopamine surface is designed for capturing target molecules. The morphology, structure and composition of the nanocomposites are characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectrometry (XPS). The resulting Fe3O4/polydopamine/Au composite NPs show not only a strong magnetic response to an externally applied magnetic field, but are also highly specific to protein bovine hemoglobin (BHb), and removal of abundant protein BHb in the bovine blood as well. This opens a novel route for future application in removing abundant protein in proteomic analysis.
Co-reporter:Min Zhang, Yipan Wu, Xizeng Feng, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2010 vol. 20(Issue 28) pp:5835-5842
Publication Date(Web):08 Jun 2010
DOI:10.1039/B925137E
In this study, we report a simple method to coat mesoporous silica onto carbon nanotubes (CNTs) via a two-step procedure. Mesoporous CNTs@SiO2 composites have been obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure after silica-coated carbon nanotubes were synthesized with the aid of the cationic surfactant CTAB. The coating process was explicitly investigated, and a possible formation mechanism of the mesoporous CNTs@SiO2 was proposed, which reveals that the ratio of CTAB/CNTs plays a critical role in the coating process. Furthermore, the pore size of the as-prepared mesoporous silica could be exactly controlled by using different amounts of the bromide surfactant CTAB. The obtained mesoporous CNTs@SiO2 composite nanomaterial was evaluated with three typical proteins, cytochrome c (Cyt c), bovine serum albumin (BSA) and lysozyme (Lyz), with different molecular sizes. The adsorption and desorption of binary mixtures of Cyt c and BSA, Cyt c and Lyz, and a ternary mixture of Cyt c, BSA and Lyz showed that the mesoporous CNTs@SiO2 are effective and highly selective adsorbents for Cyt c. The as-prepared mesoporous CNTs@SiO2 composites have shown effective performance in size-selective adsorption of biomacromolecules, demonstrating great potential in biomacromolecular separation.
Co-reporter:Ruixia Gao, Xuan Kong, Fuhai Su, Xiwen He, Langxing Chen, Yukui Zhang
Journal of Chromatography A 2010 Volume 1217(Issue 52) pp:8095-8102
Publication Date(Web):24 December 2010
DOI:10.1016/j.chroma.2010.10.121
Synthetic core–shell molecularly imprinted polymers (MIPs) were prepared for the extraction of trace triclosan in environmental water samples. The synthesis process combined a surface molecular imprinting technique with a sol–gel process based on carbon nanotubes (CNTs) coated with silica. The morphology and structure of the products were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The adsorption properties of the polymers were demonstrated by equilibrium rebinding experiments and Scatchard analysis. The prepared imprinted materials exhibited fast kinetics, high capacity and favorable selectivity. The process of synthesis was quite simple and different batches of MIPs and non-imprinted polymers (NIPs) showed good reproducibility in the template binding. The feasibility of determination of triclosan from real samples was testified using spiked river and lake water samples. The recoveries of river water and lake water samples were ranged from 92.1 to 95.3% and 90.7 to 93.6%, respectively, when the environmental water samples were spiked with 0.1, 0.3, and 0.5 μg L−1 of TCS. In addition, the reusability of MIPs and NIPs without any deterioration in capacity was demonstrated for at least 10 repeated cycles.
Co-reporter:Min Zhang, Xihao Zhang, Xiwen He, Langxing Chen, Yukui Zhang
Materials Letters 2010 Volume 64(Issue 12) pp:1383-1386
Publication Date(Web):30 June 2010
DOI:10.1016/j.matlet.2010.03.032
This paper described a facile sol–gel method to synthesize silica-coated multi-walled carbon nanotubes (MWCNTs) using anionic surfactant sodium dodecyl sulfate (SDS) for the first time. This method is quite simple and easy to operate, the uniformly silica shell could be a readily controlled ratio of two silane agents of 3-aminopropyltriethoxysilane and tetraethoxysilane, and more suitable for large-scale production. The resulting CNTs@SiO2 composites are characterized by transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy. It is of interest to note that the mesoporous CNTs@SiO2 materials can be obtained via the extraction or the calcination process and mesoporous property was investigated by N2 adsorption–desorption analysis.
Co-reporter:Xiangli Sun, Rui Liu, Xiwen He, Langxing Chen, Yukui Zhang
Talanta 2010 Volume 81(Issue 3) pp:856-864
Publication Date(Web):15 May 2010
DOI:10.1016/j.talanta.2010.01.029
In this study, we described a simple and effective modification procedure to prepare poly (methacrylate-co-ethylene glycol dimethacrylate) monolithic columns functionalized with 3-aminophenylboronic acid. The column morphology, pore size and specific surface area of the fabricated monolith were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and mercury intrusion porosimeter, respectively. The frontal analysis was carried out for dynamic loading capacity of the model protein on the modified column. The chromatographic performance of the cation-exchange monolith was evaluated through separating a mixture of five proteins such as lysozyme, cytochrome c, ribonuclease A, trypsin and bovine serum albumin and one-step purification of lysozyme from egg whites, and the expected results were obtained. In addition, the functionalized column was used to refold ribonuclease A and cytochrome c, and this procedure was monitored by circular dichroism and fluorescence spectroscopy. Compared with the conventional dilution refolding method, the ion-exchange chromatography refolding method developed here is more effective for specific bioactivity recovery.
Co-reporter:Min Zhang;Dan Cheng;Xiwen He ;Langxing Chen ;Yukui Zhang
Chemistry – An Asian Journal 2010 Volume 5( Issue 6) pp:1332-1340
Publication Date(Web):
DOI:10.1002/asia.200900463
Abstract
Magnetic silica-coated magnetite (Fe3O4) sub-microspheres with immobilized metal-affinity ligands are prepared for protein adsorption. First, magnetite sub-microspheres were synthesized by a hydrothermal method. Then silica was coated on the surface of Fe3O4 particles using a sol–gel method to obtain magnetic silica sub-microspheres with core-shell morphology. Next, the trichloro(4-chloromethylphenyl) silane was immobilized on them, reacted with iminodiacetic acid (IDA), and charged with Cu2+. The obtained magnetic silica sub-microspheres with immobilized Cu2+ were applied for the absorption of bovine hemoglobin (BHb) and the removal of BHb from bovine blood. The size, morphology, and magnetic properties of the resulting magnetic micro(nano) spheres were investigated by using scanning microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and a vibrating sample magnetometer (VSM). The measurements showed that the magnetic sub-microspheres are spherical in shape, very uniform in size with a core-shell, and are almost superparamagnetic. The saturation magnetization of silica-coated magnetite (Fe3O4) sub-microspheres reached about 33 emu g−1. Protein adsorption results showed that the sub-microspheres had a high adsorption capacity for BHb (418.6 mg g−1), low nonspecific adsorption, and good removal of BHb from bovine blood. This opens a novel route for future applications in removing abundant proteins in proteomic analysis.
Co-reporter:Xiangli Sun, Dong Lin, Xiwen He, Langxing Chen, Yukui Zhang
Talanta 2010 Volume 82(Issue 1) pp:404-408
Publication Date(Web):30 June 2010
DOI:10.1016/j.talanta.2010.03.016
A simple one-step in situ “click” modification strategy was developed for the preparation of hydrophobic organic monolithic columns for the first time. The column morphology and surface chemistry of the fabricated monolithic columns were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, respectively. The chromatographic performances of the C8/C18 “click” monoliths were evaluated through the separation of a mixture of five proteins such as ribonuclease A, soybean trypsin inhibitor, cytochrome c, bovine haemoglobin and bovine serum albumin. Compared with the blank column, the higher hydrophobicity stationary phases obtained from the “clicked” modification have longer retention times and higher resolution for the five proteins. The separation of five proteins mixture on click C18 monolith with gradient elution at different flow rates was also investigated, the baseline separation of five proteins could be achieved at three different flow rates.
Co-reporter:Lin Li;XiWen He;LangXing Chen;YuKui Zhang
Science China Chemistry 2009 Volume 52( Issue 9) pp:1402-1411
Publication Date(Web):2009 September
DOI:10.1007/s11426-009-0182-0
In this research, a surface imprinting strategy has been adopted in protein imprinting. Bovine hemoglobin surface-imprinted polystyrene (PS) nanoparticles with magnetic susceptibility have been synthesized through multistage core-shell polymerization system using 3-aminophenylboronic acid (APBA) as functional and cross-linking monomers. Superparamagnetic molecularly imprinted polystyrene nanospheres with poly(APBA) thin films have been synthesized and used for the first time for protein molecular imprinting in an aqueous solution. The magnetic susceptibility is imparted through the successful encapsulation of Fe3O4 nanoparticles. The morphology, adsorption, and recognition properties of superparamagnetic molecularly imprinted polymers (MIPs) have been investigated using transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometer. Rebinding experimental results show that poly(APBA) MIPs-coated superparamagnetic PS nanoparticles have high adsorption capacity for template protein bovine hemoglobin and comparatively low nonspecific adsorption. The imprinted superparamagnetic nanoparticles could easily reach the adsorption equilibrium and achieve magnetic separation in an external magnetic field, thus avoiding some problems of the bulk polymer.
Co-reporter:Lin Li Dr.;Xiwen He ;Langxing Chen ;Yukui Zhang
Chemistry – An Asian Journal 2009 Volume 4( Issue 2) pp:286-293
Publication Date(Web):
DOI:10.1002/asia.200800300
Co-reporter:Xiangli Sun, Xiwen He, Yukui Zhang, Langxing Chen
Talanta 2009 Volume 79(Issue 3) pp:926-934
Publication Date(Web):15 August 2009
DOI:10.1016/j.talanta.2009.05.033
A novel solid phase extraction (SPE) method for determination of tetracyclines (TCs) in milk and honey samples by molecularly imprinted monolithic column was developed. Using tetracycline (TC) as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, methanol as the solvent, cyclohexanol and dodecanol as the mixed porogenic solvents, a TC imprinted monolithic column was prepared by in situ molecular imprinting technique for the first time, and the optimal synthesis conditions and the selectivity of TC imprinted monolithic column were investigated. The interfering substances in food samples and TCs can be separated successfully on imprinted column. Molecularly imprinted solid phase extraction (MISPE) coupling with C18 column was used to determinate the TCs in milk and honey. The recoveries of this method for six tetracyclines antibiotics such as tetracycline (TC), oxytetracycline (OTC), minocycline (MINO), chlortetracycline (CTC), metacycline (MTC) and doxycycline (DTC) were investigated, and high recoveries of 73.3–90.6% from milk samples and 62.6–82.3% from honey samples were obtained. A method for determination of TCs at low concentration level in milk and honey samples was successfully developed by using the monolithic column as the precolumn for solid phase extraction of six TCs compounds.
Co-reporter:Xin Wang, Lianyan Wang, Xiwen He, Yukui Zhang, Langxing Chen
Talanta 2009 Volume 78(Issue 2) pp:327-332
Publication Date(Web):30 April 2009
DOI:10.1016/j.talanta.2008.11.024
In this study, we synthesized Fe3O4 magnetic nanoparticles coated estrone-imprinted polymer with controlled size using a semi-covalent imprinting strategy. In this protocol, the estrone–silica monomer complex (EstSi) was synthesized by the reaction 3-(triethoxysilyl)propyl isocyanate with estrone, where the template was linked to the silica coating on the iron oxide core via a thermally reversible bond. The removal of the template by a simple thermal reaction produced specific estrone recognition sites on the surface of silica shell.The resulting estrone-imprinted polymer coating Fe3O4 magnetic hybrid nanoparticles exhibit a much higher specific recognition and saturation magnetization. The hybrid nanoparticles have been used for biochemical separation of estrone.
Co-reporter:Langxing Chen, Wenfeng Zhao, Yufen Jiao, Xiwen He, Jing Wang, Yukui Zhang
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2007 Volume 68(Issue 3) pp:484-490
Publication Date(Web):November 2007
DOI:10.1016/j.saa.2006.12.014
The water-soluble Ag/Pt core-shell nanoparticles were prepared by deposition Pt over Ag colloidal seeds with the seed-growth method using K2PtCl4 with trisodium citrate as reduced agent. The Ag:Pt ratio is varied from 9:1 to 1:3 for synthesizing Pt shell layer of different thickness. A remarkable shift and broadening of Ag surface plasmon band around 410 nm was observed. The contrast of TEM images of Ag/Pt colloids has been obtained. Various techniques, such as transmission electron microscopy (TEM), UV–vis absorption and resonance light-scattering spectroscopy were used to characterize nanoparticles. The data of TEM, UV–vis and resonance light-scattering spectrum all confirm formation of Ag/Pt core-shell nanoparticles. Resonance light-scattering and emission spectrum show the Ag and Ag/Pt core-shell nanoparticles have a nonlinear light-scattering characteristic.
Co-reporter:Ruixia Gao, Xuan Kong, Xin Wang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 44) pp:NaN17871-17871
Publication Date(Web):2011/10/05
DOI:10.1039/C1JM12414E
A general method to prepare thin, molecularly imprinted polymer (MIP) coatings on magnetic Fe3O4 nanoparticles (NPs) with a uniform core–shell structure for the recognition and enrichment of protein was developed. Four proteins (bovine serum albumin (BSA, pI = 4.9), bovine hemoglobin (BHb, pI = 6.9), bovine pancreas ribonuclease A (RNase A, pI = 9.4) and lysozyme (Lyz, pI = 11.2)) with different isoelectric points were chosen as the templates. The magnetic protein-MIPs were synthesized by combining surface imprinting and sol–gel techniques. The morphology, adsorption and recognition properties of the magnetic molecularly imprinted NPs were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy and through the use of a vibrating sample magnetometer (VSM). In comparison with the use of Lyz, BSA and RNase A as template proteins, BHb-imprinted Fe3O4 showed the best imprinting effect and the highest adsorption capacity among the four proteins. The as-prepared Fe3O4@BHb-MIPs NPs with a mean diameter of 230 nm were coated with an MIP shell that was 10 nm thick, which enabled the Fe3O4@BHb-MIPs to easily reach adsorption equilibrium. A high magnetic saturation value of 25.47 emu g−1 for Fe3O4@BHb-MIPs NPs was obtained, which endowed the adsorbent with the convenience of magnetic separation under an external magnetic field. The resultant Fe3O4@BHb-MIPs NPs could not only selectively extract a target protein from mixed proteins but also specifically capture the protein BHb from a real sample of bovine blood. In addition, different batches of magnetic MIPs showed good reproducibility and reusability for at least six repeated cycles.
Co-reporter:Min Zhang, Yipan Wu, Xizeng Feng, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2010 - vol. 20(Issue 28) pp:NaN5842-5842
Publication Date(Web):2010/06/08
DOI:10.1039/B925137E
In this study, we report a simple method to coat mesoporous silica onto carbon nanotubes (CNTs) via a two-step procedure. Mesoporous CNTs@SiO2 composites have been obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure after silica-coated carbon nanotubes were synthesized with the aid of the cationic surfactant CTAB. The coating process was explicitly investigated, and a possible formation mechanism of the mesoporous CNTs@SiO2 was proposed, which reveals that the ratio of CTAB/CNTs plays a critical role in the coating process. Furthermore, the pore size of the as-prepared mesoporous silica could be exactly controlled by using different amounts of the bromide surfactant CTAB. The obtained mesoporous CNTs@SiO2 composite nanomaterial was evaluated with three typical proteins, cytochrome c (Cyt c), bovine serum albumin (BSA) and lysozyme (Lyz), with different molecular sizes. The adsorption and desorption of binary mixtures of Cyt c and BSA, Cyt c and Lyz, and a ternary mixture of Cyt c, BSA and Lyz showed that the mesoporous CNTs@SiO2 are effective and highly selective adsorbents for Cyt c. The as-prepared mesoporous CNTs@SiO2 composites have shown effective performance in size-selective adsorption of biomacromolecules, demonstrating great potential in biomacromolecular separation.
Co-reporter:Min Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2010 - vol. 20(Issue 47) pp:NaN10704-10704
Publication Date(Web):2010/10/04
DOI:10.1039/C0JM01336F
In this study, we report a method to synthesize core–satellite structured Fe3O4/polydopamine/Au composite nanoparticles (NPs). Firstly, the Fe3O4/polydopamine composite NPs with a well-defined core–shell structure are obtained using dopamine self-polymerization to form thin, surface-adherent polydopamine films onto the surface of a Fe3O4 “core”. The polydopamine shell could be adjusted by controlling the experimental parameters such as reaction time and the reactant concentrations. Then, numerous “satellites” of gold nanoparticles were assembled on the surface of Fe3O4/polydopamine by reducing Au3+ between the Fe3O4/polydopamine solid and HAuCl4 solution. Next, 11-mercaptoundecanoic acid (11-MUA) forms a self-assembled monolayer of MUA on the surface of the Au NPs and polydopamine layer. Finally, IDA-Cu functionalized Fe3O4/polydopamine/Au composite NPs are obtained by the carboxyl groups of MUA reacting with iminodiacetic acid (IDA), charged with Cu2+. The IDA-Cu groups, acting as an “anchor”, are attached on the gold and the polydopamine surface is designed for capturing target molecules. The morphology, structure and composition of the nanocomposites are characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectrometry (XPS). The resulting Fe3O4/polydopamine/Au composite NPs show not only a strong magnetic response to an externally applied magnetic field, but are also highly specific to protein bovine hemoglobin (BHb), and removal of abundant protein BHb in the bovine blood as well. This opens a novel route for future application in removing abundant protein in proteomic analysis.
Co-reporter:Xihao Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 32) pp:NaN16526-16526
Publication Date(Web):2012/07/13
DOI:10.1039/C2JM32987E
In this study, a novel approach was developed to synthesize aminophenylboronic acid functionalized magnetic nanoparticles (NPs) via Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) ‘click’ chemistry. Firstly, azide-functional Fe3O4 NPs were obtained by a two-step chemical modification process. Then, an alkyne-phenylboronic acid molecule was connected onto the surface of magnetite by the CuAAC reaction. The morphology, structure and composition of the synthesized nanocomposites were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectrometry (XPS). Five proteins, including ovalbumin (OB), transferrin (Trf), as glycoprotein templates and lysozyme (Lyz), bovine serum albumin (BSA), horse heart cytochrome c (Cyt C) as nonglycoprotein templates are chosen as target proteins. The as-prepared click-Fe3O4@APBA NPs with a mean diameter of 23.2 nm showed a strong magnetic response to an externally applied magnetic field and exhibited a high adsorption capacity and excellent specificity towards glycoproteins in comparison with nonglycoproteins. The click-Fe3O4@APBA NPs showed the higher adsorption capacity towards glycoproteins than the nonclick-Fe3O4@APBA NPs which were synthesized through a common nucleophilic substitution reaction. The greatly enhanced adsorption capacity towards glycoproteins demonstrated that the ‘click’ method presented great superiority in ligand immobilization. Finally, the click-Fe3O4@APBA NPs could efficiently enrich glycoproteins from real egg white samples as well.
Co-reporter:Jiali Cao, Xihao Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 30) pp:NaN3632-3632
Publication Date(Web):2013/06/03
DOI:10.1039/C3TB20573H
In this study, a facile and efficient separation of abundant proteins from bovine blood using core–shell structure nanoparticles with a magnetic core and an immobilized metal affinity ligand iminodiacetic acid (IDA) chelating Ni(II) is presented. Firstly, Fe3O4 magnetic nanoparticles (MNPs) were synthesized through a solvothermal method and then were conveniently surface-modified with 3-(methacryloyloxy) propyltrimethoxylsilane as anchor molecules to donate vinyl groups. Next a high density poly(4-vinylbenzylchloride) (PVBC) shell was synthesized on the surface of silica-coated Fe3O4 MNPs via distillation–precipitation polymerization. After the PVBC shell reacted with iminodiacetic acid (IDA) in alkaline aqueous solution, the magnetite was charged with Ni2+ to form Ni(II)-IDA functionalized hybrid Fe3O4@PVBC@IDA-Ni MNPs. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and a vibrating sample magnetometer (VSM) were employed to evaluate the size, morphology and magnetic property of the resulting magnetic nanospheres. The high saturation magnetization (48.1 emu g−1) provides the materials with the convenience of magnetic separation under an external magnetic field and they can be subsequently reused. The core–shell Fe3O4@PVBC@IDA-Ni MNPs exhibit excellent performance in the separation of protein bovine hemoglobin (BHb), and the binding capacity is as high as 1988 mg g−1. In addition, the Fe3O4@PVBC@IDA-Ni MNPs can be used in selective removal of abundant protein Hb in the bovine blood samples. This opens a novel route for its future application in removing abundant protein in proteomic analysis.
Co-reporter:Xihao Zhang, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 21) pp:NaN3262-3262
Publication Date(Web):2014/03/17
DOI:10.1039/C4TB00379A
Biomedical sciences, and in particular biomarker research, demand efficient glycoprotein enrichment platforms. In this paper, a facile and efficient approach combining distillation–precipitation polymerization (DPP) and click chemistry was developed to synthesize boronic acid ligand-modified magnetic nanoparticles for the enrichment of glycoproteins. Due to the relatively large amount of benzyl chloride groups introduced by DPP on the magnetic core, which easily can be transferred into azide groups, the alkyne–phenylboronic acid ligands were immobilized onto the surface of Fe3O4 with high efficiency via the Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) ‘click’ reaction. The morphology, structure and composition of the resulting core–shell Fe3O4@poly(4-vinylbenylchloride)@amidophenylboronic acid (Fe3O4@pVBC@APBA) nanocomposites were characterized by transmission electron microscopy, X-ray powder diffraction, vibrating sample magnetometry, Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray photoelectron spectrometry. The Fe3O4@pVBC@APBA microspheres held a ∼50 nm polymeric shell, and exhibited high magnetic response to an external magnetic field. The binding results demonstrated that Fe3O4@pVBC@APBA possessed high adsorption capacity and remarkable selectivity to glycoproteins. Moreover, the glycoproteins in the egg white sample could be enriched under physiological conditions (pH 7.4) as well, due to the lower pKa value of the alkyne–phenylboronic acid ligand. The high stability and selectivity of Fe3O4@pVBC@APBA for the glycoproteins were retained over several separation cycles. This boronate affinity material has potential applications in biomedical and biotechnological fields including drug delivery and biosensing.
Co-reporter:Xiangyang An, Xiwen He, Langxing Chen and Yukui Zhang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 36) pp:NaN6133-6133
Publication Date(Web):2016/08/15
DOI:10.1039/C6TB01489E
Biomedical sciences, and in particular biomarker research, demand efficient glycoprotein enrichment platforms. In this work, a facile and efficient method was developed to synthesize boronic acid polymer brushes immobilized on magnetic graphene oxide via surface initiated atom transfer radical polymerization (SI-ATRP) for the selective enrichment of glycoproteins from complex biological samples. The magnetic graphene oxide (GO@Fe3O4) nanocomposites were prepared by a solvothermal reaction, providing an ultrahigh surface area and allowing fast separation. Through the self-assembly procedure, the pyrene-based initiators (GO@Br) of SI-ATRP were easily functionalized on the GO sheet via noncovalent π–π interaction between pyrene and GO. Finally, the well-defined and high density poly(4-vinylphenylboronic acid) brushes (GO@PVPBA) via SI-ATRP were successfully fabricated. The morphology and structure of GO@Fe3O4, GO@Br, and GO@PVPBA nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Fourier transform-infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The selective recognition capability of GO@PVPBA nanocomposites was demonstrated by the selective enrichment of glycoproteins from a complex system consisting of standard proteins ovalbumin (OVA), transferrin (Trf), bovine serum albumin (BSA), and lysozyme (Lyz). Furthermore, the GO@PVPBA nanocomposite also exhibited a high binding capacity up to 514.8 and 445.9 mg g−1 for OVA and Trf, respectively, and was applied to capture directly glycoproteins from the egg white samples.
![4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 6-[[(2-ethoxy-1-naphthalenyl)carbonyl]amino]-3,3-dimethyl-7-oxo-,(2S,5R,6R)-](http://img.cochemist.com/ccimg/200/147-52-4.png)
![4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 6-[[(2-ethoxy-1-naphthalenyl)carbonyl]amino]-3,3-dimethyl-7-oxo-,(2S,5R,6R)-](http://img.cochemist.com/ccimg/200/147-52-4_b.png)
![Boronic acid, B-[3-[(1-oxo-4-pentyn-1-yl)amino]phenyl]-](/data/chemimg/139400/1392407-74-7.png)
![Boronic acid, B-[3-[(1-oxo-4-pentyn-1-yl)amino]phenyl]-](/data/chemimg/139400/1392407-74-7_b.png)
